The prior art shows many inflatable seat belt systems; one such system is shown in the PCT patent application WO2009155534A1. This system incorporates two retractors, one to retract the shoulder belt and another to retract the lap belt. Ends of the shoulder belt and the lap belt are fastened securely to a tongue and the shoulder belt includes an inflatable air bag. This system displays superior performance and utilizes a tongue/buckle combination through which inflation gas flows into the inflatable air bag.
Other systems have proposed the use of a single retractor system, however the performance of these systems has been found to be lacking. For example, if the inflatable belt is incorporated as part of the shoulder belt, the thickness of this combination is increased substantially compared to that of a conventional shoulder belt alone. In this type of system it has proved difficult if not impossible to permit the inflatable belt/shoulder belt combination to traverse over the shoulder-high belt loop, which is also referred to as a D-ring.